The current Standard of Care for the rehabilitation of severely burned children is to discharge the patient from the hospital, with a written set of instructions for physical and occupational therapy activities at home, in an unsupervised environment. These activities do not significantly impact the persistent and extensive skeletal muscle catabolism and weakness characteristic of severe burns. The central hypothesis of this grant is that a supervised anld structured aerobic and resistance exercise program implemented at hospital discharge in severely burned children will improve physical structure and function, allowing for an improvement in quality of life (QOL). We propose the following specific aims (SA): SA1 will test the hypothesis that in severely burned children, a supervised and structured exercise program will significantly increase muscle mass and bone mass more than the current Standard of Care. SA2 will test the hypothesis that in burned children, <p supervised and structured exercise program will significantly increase peak aerobic capacity and muscle strejngth more than the current Standard of Care. SA3 will test the hypothesis that a supervised and structure'd exercise program will significantly increase net protein synthesis compared to the current Standard of Care in burned children and lead to an improvement in lean mass and muscle strength. SA4 will test the hypothesis that in burned children, a supervised and structured exercise program will significantly improve QOL more than the current Standard of Care. Primary outcomes are peak aerobic capacity assessed with a. cardiopulmonary exercise test;muscle strength, using leg dynamometry, muscle mass assessed usingidual X-ray absorptiometry, and net protein balance assessed using urea enrichment. Finally, psychosocial health using the Child Health Questionnaire, (PF-28 and CF-87) will be assessed. Assessment of physical function, and QOL will be done at hospital discharge, at the end of the 12-week exercise program, at 12 months, and at 24 months post burn. Assessment of net protein balance will be done at hospital discharge, c^nd at the end of the 12-week exercise program. It is expected that these proposed studies will expand the present knowledge of physical and psychosocial rehabilitation programs for severely burned children. Furthermore, we believe that these proposed studies will result in novel and clinically relevant data that may jn turn establish new guidelines for the Standard of Care of burned children.